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  • Created by: Ellie
  • Created on: 05-05-12 14:10


Take care - enzymes are not living things. They are just special proteins that can break large molecules into small molecules. Different types of enzymes can break down different nutrients:

  • carbohydrase or amylase enzymes break down starch into sugar

  • protease enzymes break down proteins into amino acids

  • lipase enzymes break down fats into fatty acids and glycerol.

digestive enzymes are special biological molecules that speed up chemical reactions. they break down large insoluble food molecules into smaller soluble molecules. they are made of proteins and are a very specific shape. each enzyme will only work on specific food molecules.

the catalytic cycle of an enzyme:

  • the enzyme is available with an empty active site
  • then the substrate sucrose binds to the enzyme with an induced fit.
  • then the substrate is converted to products
  • finally being released as products

to have a balanced diet you should use sparingly fats oils and sweets, you should have 2 to 3 servings of dairy, meat poultry, nuts, vegetables and fruits. you should have 6 to 11 servings of bread cereal rice and pasta.

Elderly people need less food as they tend to be less active and require less energy. athletes need more food for extra protein to build muscles and because they need more energy. pregnant women need extra food, protein, calcium and iron. an office worker needs less energy due to a less active job. babies need lots of protein for growth and calcium for bones and teeth. a manual worker needs more energy due to active nature of work. people who are growing and people with medical requirements such as diabetes need different nutrient requirements such as more or less food.

Carbohydrates. for example glucose. glucose id a small molecule that dissolves easily in water. it is present in all foods such as cakes sweets and fruit.Complex carbohydrates. for example starch. starch is many glucose molecules pulled together to make a big molecule. starch is insoluble  and too large to pass through cell membranes. it is present in foods such as bread pasta and flour.fats or lipids. fat molecules consist of two parts; 3 fatty molecules joined to a glycerol molecule. fats do not dissolve in water. they are present in foods such as eggs cheese milk and butter.proteins. proteins are long chain molecules made up of many amino acids joined together. a different order of amino acids…


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